When I looked at. Securemotion with a view to installing it in our MH one of the guides that I read on it by Truma, said that it cannot be retrofitted as the pipe work has to be of a particular standard.
I did not go ahead with it but it might be one reason why it is not connected, hopefully a suitably qualified gas engineer for LPG for mobile uses will know what the restrictions are, if my memory is inaccurate.
Any typo that I make means the errorists win.
Any comments above are only MY OPINION and should be read as that.